1. Field of the Invention
The present invention relates to a game betting device which enables players to bet game chips during games using a roulette wheel or the like.
2. Discussion of the Background
JP-A 2004-105321 and JP-A 2004-102953 disclose techniques of having radio waves transmitted from an X-side transmission antenna and a Y-side transmission antenna, having radio waves generated from fluxes that are vertical to a table at the X-Y cross point, and then reading IDs of RFID tags (radio frequency identification tags) provided in chips placed on the table at this cross point, the reading successively performed for each bet portion.
A betting board for use in table games such as roulettes in casinos and the like has an upper surface having frames displayed thereon, and the upper surface is partitioned into a plurality of sections (bet portions) by the frames. Further, players are enabled to bet by placing chips on the upper surface. Thereafter, information in the RFID tags in the chips betted on the respective bet portions are read, as in the techniques of JP-A 2004-105321 and JP-A 2004-102953.
FIG. 12 is a plan view of a portion of an upper surface 101 of a betting board. The upper surface 101 has a plurality of bet portions 103 defined by frames 102. The same figure illustrates some of the plurality of bet portions 103. In the case of such a betting board, in order to provide RFID tags in betting chips and to enable reading of information in the RFID tags in the chips which have been betted, it is possible to employ the following structure.
Namely, as illustrated in FIG. 13, a plurality of loop-shaped antennas (antenna coils) 104 for reading RFID tags are provided in the betting board. The antennas 104 are provided in association with the respective bet portions 3 and are placed along the frames 102 which form the boundaries of the bet portions 103. The antennas 104 of A1 to A6 in FIG. 13 are associated with the respective bet portions 103 in FIG. 12.
FIG. 14 illustrates positional relationships between chips 105 placed on the upper surface 101 and the antennas 104. In the example of the same figure, the RFID tags in the respective chips 105 can be read by the antennas 104 of A1, A5 and A6. Further, usually, chips are placed such that they are stacked on the upper surface 101, and such plurality of chips stacked at the same position can be also read by a single antenna 104. Further, it is possible to read the RFID tags in all the chips 105 placed on the betting board, by performing operations for reading the RFID tags while successively changing over among the plurality of antennas 104.
The bet positions where the chips 105 can be placed on the betting board during roulette games include bet positions on both of the adjacent bet portions 103 as illustrated in FIG. 15, in addition to bet positions which fit in respective bet portions 103 on the betting board as illustrated in FIG. 14. In the example of FIG. 15, for the chip 105 placed on an antenna 104 of A1 (the bet portion 103 having the antenna 104 of A1 placed therein) and an antenna 104 of A4 (the bet portion 103 having the antenna 104 of A4 placed therein), both of the antennas 104 can read the RFID tag in this chip 105 when the output of reading radio waves is sufficient; it is therefore possible to determine that this chip 105 is placed on the antenna 104 of A1 and the antenna 104 of A4. On the other hand, for the chip 105 placed on the four antennas 104 of A2, A3, A5 and A6, the areas of the chip 105, overlaid on the respective antennas 104, are significantly small, which makes it difficult to read the RFID tag provided in this chip 105. Further, in cases where a plurality of chips 105 are stacked, it is almost impossible to read the RFID tags in the chips 105 stacked at upper portions.
FIG. 16 illustrates an exemplary structure of a betting board for overcoming the aforementioned problem. In the example of FIG. 16, there are provided antennas 104 having sizes which are half that of the aforementioned example. Further, the antennas 104 are placed at the center portions of the respective bet portions 103 and at the boundary portions between adjacent bet portions 103 (the positions of the four corner portions of each rectangular bet portion 103 and the positions between these corner portions). With this placement, it is possible to read the RFID tag in a chip 105 placed at the center portion of a bet portion 103, by the antenna 104 placed at the center portion of this bet portion 103. Further, it is possible to read the RFID tag in a chip 105 placed at the boundary portion between adjacent two bet portions 3, by the antenna 104 placed at this boundary portion. Further, it is possible to read the RFID tag in a chip 105 placed at the corner portions of four bet portions 103 facing to one another, by the antenna 104 placed at the corner portions.
As described above, by reducing the size of the antennas 104 and densely placing many antennas 104 in association with the upper surface 101 of the betting board, it is possible to accurately read the chips 105 placed at various positions on the betting board.
Furthermore, in cases of using a betting board for roulette games, there is a need for reading the RFID tags in all betted chips 105 within a limited time. Accordingly, as the number of antennas 104 is increased, the time for reading RFID tags allocated to each single antenna 104 becomes significantly decreased.
Further, when the antennas 104 generate electromagnetic waves, more specifically magnetic fields, the magnetic fields will cause an RFID tag to generate electricity and to return signals to the antennas 104. At this time, in cases where the RFID tag performs modulation thereon, the RFID tag turns on and off a resistance or capacitance which forms a load so as to change the electric current flowing through the coil in the RFID tag, and generates a counter magnetic field, thus realizing load modulation.
The contents of JP-A 2004-105321 and JP-A 2004-102953 are incorporated herein by reference in their entirety.
However, in the aforementioned example, signals returned from the RFID tags through the load modulation are significantly smaller than the magnetic fields outputted from the antennas 104 and, in a case where noise and the like are mixed therewith, it becomes impossible to correctly read the RFID tags.
Accordingly, when high-speed switching among the many antennas 104 is performed in order to read the RFID tags in the respective chips 105, this high-speed switching among the antennas 104 will induce high-frequency noise, thereby causing a problem of making it impossible to correctly read the information in the RFID tags.
It is an object of the present invention to make it possible to accurately read the RFID tags in all chips placed at respective positions on a betting board, by preventing the RFID tags from being unreadable due to the generation of high-frequency noises.